Presenting his book, "2052", Jorgen Randers starts with a bold statement: "I will not tell you what the future could be, but what the future will be". You would think that this shows quite a bit of hubris but, if you follow Randers' reasoning, you'll see that he has a point.

Randers is one of the authors of the famous "The Limits to Growth" report to the Club of Rome. Published in 1972, the book caused quite a stir and was widely misinterpreted as a prophecy of doom. It wasn't so and, in his talk, Randers summarizes what he and the others did. They didn't make any prophecy but, rather, they created a 'fan' of 12 different scenarios for the future of the world up to 2100. Some of these scenarios involved decline and collapse of the economy, some involved stabilization and prosperity. Whether one or the other set of scenarios would unfold depended on whether humankind made the right or the wrong choices in dealing with pollution, resource exploitation, and population growth.

One problem with the "The Limits to Growth" was that the authors never specified by what mechanisms humankind could develop the consensus necessary to make the right choices, which all involved some sacrifices in the short term. After 40 years of work, Randers has arrived to a conclusion: there are no such mechanisms. The right choices were not made and never will be.

Today, Randers says, there is no more a fan of good and bad scenarios: there is only one; and it is not pleasant. It can only be the decline of our society, constrained by overpopulation, declining resource availability, and widespread damage caused by pollution and climate change. The start of the decline may come earlier or later; collapse may be faster or slower, but the shape of the future is determined.

Randers maintains that there is a simple way to describe the reasons that are taking us to this unpleasant future: people always make the choice that involves the least costs in the short term. The problem is all there: as long as we always choose the easiest road, we have no control on where we are going.

Imagine you are lost in a forest. Would you think that always choosing the easiest path in front of you could take you home? But this is what we are doing: even though we should know that this is not the way to go where we would like to be. We are unwilling, for instance, to invest in renewable energy as long as fossil fuels are even slightly less expensive and we can neglect their external costs in the form of pollution and climate change. But this choice is based on short term consideration and it will cause us terrible long term damage.

Why are we unable to do better? Here, Randers proposes that "short-termism" is deeply ingrained in people's minds and is reflected in our democratic decisional system. He has been accused to be against democracy, but he maintains that he has nothing against democracy: the problem is that democracy is the result of human short-termism. He makes the example of an enlightened politician who decides to introduce a carbon tax. Soon, voters discover that the carbon tax is making gasoline and electricity more expensive. As a consequence, that politician won't be re-elected. It is simple and it happens all the time.

Of course, you might object that if the public were to be educated about climate change, then people would accept a carbon tax - actually they would clamor for it. Maybe; but Randers is skeptical. He says that he has spent decades of his life training generations of decision-makers in sustainability and ecosystem science. And he has seen those trained generations taking exactly the same wrong decisions that the previous, untrained, generations were taking.

Human nature is difficult to overcome. Randers recounts how he and his colleagues had been discussing about the size of a natural disaster that would wake the public to the reality of ecosystem destruction. Then Hurricane Katrina came and, later on, Sandy. Both where disasters as big as they can be. But they fell flat as wake up calls: the public didn't react. Today, three Americans out of eight still think that global warming is a hoax.